PALM SPRINGS, Calif. — Inside a seemingly innocuous Southern California home was a dark and disturbing secret that had gone largely unnoticed in two different states for more than 20 years.

Thirteen siblings lived at the home in Perris, a small suburban community about 75 miles east of Los Angeles. They lived a secluded life behind a veil that was lifted just before 6 a.m. on Jan. 14, revealing the horrors that the Turpin children suffered most of their lives.

After two years of planning, a 17-year-old girl escaped the home and dialed 911 using a cellphone she had hid from her parents. For 20 minutes, a dispatcher listened as the teen, who had the voice of a child, described horrendous treatment David and Louise Turpin allegedly levied on their children.

"They are chained up in their bed,” the Turpin daughter said. "I wanted to call y’all so you can help my sisters."

David and Louise Turpin were arrested on Sunday after Riverside County sheriff deputies found siblings malnourished in their Perris, Calif. home, Tuesday, January 16, 2018.(Photo11: Zoe Meyers/The Desert Sun)

The stunning 911 call was made public for the first time last week in Riverside County Superior Court during the preliminary hearing for David and Louise Turpin. The evidence presented by the prosecution included disturbing photographs of the children and was more than sufficient to ensure the Turpins will stand trial in August for all but one of the 50 counts against them.

By the time the children were rescued, they were an average of 32 pounds underweight and their diets mostly consisted of peanut butter and jelly sandwiches, baloney sandwiches and frozen burritos.

They wore feces-stained clothing and were severely under educated. One investigator testified a 22-year-old son said he had only completed the third grade and guessed that his education maxed out at the 10th grade.

The preliminary hearing further established that, for everything the public knew about the Turpin children after the rescue, their lives were so much worse.

Abandoned in Texas

While little has been revealed about why the Turpins became so abusive to their children, the earliest known details trace back to their lives near Fort Worth, Texas, in the 1990s, before some of the children were even born.

The family lived in a rural area between Fort Worth and Waco in a double-wide mobile home. Neighbors rarely saw them.

A former neighbor said the Turpins left behind a home filled with feces and padlocks. Recently, a classmate posted on Facebook that one of the daughters was in his third-grade class and was frequently bullied for wearing the same clothes and coming to class unshowered.

Testimony provided by investigators during the preliminary hearing established that the children were abandoned at their home after being"conditioned" through years of severe abuse.

David, 3rd from the left, and Louise Turpin, left, appear for their preliminary hearing with their lawyers at the Riverside Hall of Justice on Wednesday, June 20, 2018 in Riverside. The Turpins are charged with multiple counts of torture involving their children.(Photo11: Richard Lui, The Desert Sun-USA Today Network)

The children said in interviews with investigators that there was a strict and vicious system of punishment for any disobedience. Physical hitting was the first level of punishment and was followed by beatings with a paddle, an oar, and then a metal-tipped tent pole.

"If this didn’t work, they were put in cages," Riverside County Deputy District Attorney Kevin Beecham said during the hearing.

The metal cage was 35 square feet with an opening for the parents to feed their captive children. If that didn’t suffice, the parents used a dog kennel, the children told investigators.

Defense attorneys argued this evidence should be excluded from the case because it happened outside Riverside County’s jurisdiction. But the prosecution successfully countered that the abuse in Texas served as conditioning to let the parents live independently while their children lived in fear.

In this Oct. 29, 2011, image made from a video provided by A Elvis Chapel, David Allen Turpin, left, and his wife, Louise Anna Turpin, right, celebrate a renewal of their wedding vows with Elvis impersonator Kent Ripley in Las Vegas. The couple was arrested Sunday, Jan. 14, 2018, after authorities found their malnourished children in their home in suburban Perris, Calif., 60 miles (96 kilometers) southeast of Los Angeles. The couples' children were so emaciated the older ones still looked like children. (A Elvis Chapel via AP)(Photo11: AP)

A short drive away, the parents were staying in an apartment while their children struggled to survive on their own. The older children acted as parents, changing diapers and doling out fierce punishments — as David and Louise Turpin would have seen fit.

"The Turpins abandoned their children for three years," Beecham said.

In a stunning moment in court, the prosecution said the oldest daughter escaped the horrific life in the trailer. But without a basic education or documentation, like a driver’s license, she could not get a job or care for herself. She ultimately called Louise to come pick her up and returned home to the abuse.

This, the prosecution argued, was the result of years of conditioning and it ultimately ensured that the children would stay obedient through their move to California. Despite the arguments of the defense, this evidence was found to be “extraordinarily relevant,” Judge Bernard Schwartz said.

"Clearly all of that was done for a purpose, whether that was to punish the children or to condition them to do what the parents wanted them to do," he said.

Physical abuse escalates in Murrieta

The family moved to California in June 2010 due to David Turpin’s job with defense contractor Northrop Grumman, and they settled in a two-story home in Murrieta.

Residents rarely saw the family, unless it was late at night when children were loaded into a van for an unknown destination. But on at least one occasion, a neighbor saw them from the outside when undrawn curtains revealed odd activity inside the Turpin house.

"They would march for hours in the middle of the night," Mike Clifford, who lives across from the home, said in January. "You could see them pass one window and come around."

Riverside District Attorny Michael Hestrin gives a press conference at the D.A. office in Riverside on January 18, 2018 regarding the charges of children endangerment and torture against David and Louise Turpin after multiple children and adults were found in their care to be under precarious living conditions. (Photo11: Omar Ornelas/The Desert Sun )

David Turpin filed paperwork with the California Department of Education indicating his children were being home schooled. However, in violation of standards, they weren’t following a curriculum, and most of them didn’t have an education past third-grade.

"We don’t do school," the daughter said during the 911 call.

In response to the investigation, lawmakers proposed legislation that would require stricter regulations for home schools. Eight years of fraudulent filings are grounds for charges of perjury against David Turpin in the coming trial.

He also is charged with sexual abuse stemming from incidents that allegedly began in the Murrieta home about five years ago.

The sibling, who escaped the Perris home, told authorities she was 12 years old when her father pulled her pants down and placed her on his lap and tried to kiss her on her lips. She told investigators the encounter abruptly ended when David Turpin heard his wife walking toward the room, and he advised the child not to talk about it, according to prosecutors.

David Turpin’s attorney argued the sexual abuse never happened and he was never home when his wife abused their children as she enforced the family’s strict rules.

Investigators described a home life where children regularly had their hair pulled, were hit, and were thrown across rooms. Louise Turpin allegedly threw a child down the stairs and delayed medical treatment.

On another occasion, she forced a daughter to stand in the corner of a bathroom as punishment for playing with a Barbie doll. The malnourished girl became dizzy after two hours and fractured her jaw after falling to the ground, investigators say. A sister tried to alert Louise Turpin to her sibling’s condition, but the mother chastised her for interrupting a phone call.

Once they got the girl to a hospital, Louise Turpin allegedly advised her to tell doctors that she injured herself after slipping on water, according to prosecutors.

Final years before an escape

The Turpins remained secretive when they moved to their Perris house in 2014, but rare moments of interaction with the public emerged.

The oldest son attended classes at Mount San Jacinto Community College, where classmates described him as shy, frail and visibly hungry. Investigators say Louise Turpin would go to the campus with her son, wait outside the classroom and then immediately escort him home.

Meanwhile, the family participated in a community holiday decorating contest two years ago. They built a Nativity scene in their front yard with hay for the manger, the Nativity star in a window and Santa Claus and his sleigh near the garage.

One of the decorations still hung by their window this year in the days after the children’s rescue, which apparently occurred just days before the family was going to move to Oklahoma.

But for the children, life in Perris remained harrowing, and photos depicting their abuse in the home were presented during the preliminary hearing.

In one photo, a girl is tightly chained around her frail torso. Her long dark hair covers the pale skin of her face, her eyes cast down and away. She sits on her knees on a filthy mattress thrown on the floor in front of a pair of bunk beds. Two open padlocks are visible on the mattress in a photo taken after the rescue.

Riverside District Attorney Michael Hestrin gives a press conference at the D.A. office in Riverside on January 18, 2018 regarding the charges of children endangerment and torture against David and Louise Turpin after multiple children and adults were found in their care to be under precarious living conditions. (Photo11: Omar Ornelas/The Desert Sun)

An additional photo showed another girl chained to a bedpost, sitting on the floor with her thin wrists shackled tightly.

The daughter who made the 911 call told investigators that two of her sisters had been chained for up to two months. She did not know the names of the months and had trouble calculating time.

Older Turpin children were more capable of estimating how long they were constrained and one of them claimed he was imprisoned “off and on for six and half years,” an investigator testified.

The escaped daughter was allegedly punished fiercely for watching a Justin Bieber video on a borrowed cellphone. She claimed Louise Turpin choked her, telling the girl she wanted to die and go to hell.

These threats helped motivate the daughter to make the 911 call, the prosecution argued. It really hurt her when her mother told her that she was evil and was “worse than the devil,” Riverside County Sheriff’s Deputy Manuel Campos testified.

“She thought of herself as a good Christian,” he said of the girl.

The aftermath

The prosecution presented evidence that all the children, except for the youngest, were severely malnourished. Two of the daughters will never be able to have children and several suffer from psychosocial dwarfism — a growth disorder caused by severe stress.

These disorders, prosecutors say, discouraged the children from seeking help.

The defense attempted to sow confusion in the case by confirming that there was a phone in the Perris home. Some of the children had access to social media and one of them even made a Twitter friend with someone in India.

Media gathers outside of the home where David and Louise Turpin are accused of holding 13 of their children prisoner inside their home, Tuesday, January 16, 2018.(Photo11: Zoe Meyers/The Desert Sun)

But Beecham stressed this was all kept secret from the parents who instilled a fear —almost a responsibility — in their children to remain obedient and even inform them whenever any of the siblings misbehaved.

This may have been evident on Jan. 14, when a second sibling tried to participate in the escape before returning home out of fear of punishment, investigators say.

The other sibling continued the escape attempt and managed to call authorities.

"Two of my sisters, one of my brothers are tied up," she told the dispatcher in her small, but steely voice.

Riverside County Sheriff’s Deputy Daniel Brown testified that one of the girls looked out the window the day her sister escaped and saw multiple police cars.